Research On Structure-function Relationship And Application Characteristics Of Hydrogenated Transformer Oil

As the main insulating medium of power transformer, transformer oil plays an importantrole in cooling, insulating and eliminating the electrical arc. It’s significant for the transformerto work in a good condition. Naphthenic base crude oil is the ideal raw material. However, thenaphthenic crude oil in the world is scare, which only accounts for2%of crude oil on theearth. In recent years, the naphthenic crude oil was in situation of short supply. Therefore, it isnecessary to research the petroleum products with similar performance to naphthenic base oil.The relationship between group composition and performance of paraffinic andnaphthenic transformer oil was discussed firstly. The result shows that the pour point andoxidation stability substantially have inversely proportional relationship with CP(alkane). Thecontent of long straight-chain hydrocarbon and unsaturated carbon in non-cyclic alkyl crudeoil has been reduced efficiently through hydrocracking, isodewaxing and hydrorefining. Itcould significantly reduce the pour point and improve the oxidation capability of transformeroil.A comprehensive assessment was established to evaluate the performance ofhydrogenated transformer oil. The electrical, physical and chemical properties ofhydrogenated transformer oil have been researched. The sludge solubility test was conducted.Referring to the German Standard, the chemical composition variation and the influence oftransformer oil aging on electrical and physic-chemical properties were studied in the agingprocess. And the correlation between hydrogenated transformer oil’s properties and itschemical composition variation were also investigated. The results show that thehydrogenated transformer oil has excellent electrical properties, but it has more advantages interms of density, flash point, total sulfur content and so on, compared with naphthenictransformer oil. It is safer and has longer lifetime in service. The hydrogenated transformer oilhas good sludge solubility. The Baader test shows that the curves of tanδ, CN, interfacialtension and kinematic viscosity all have inflection point after aging112hours. Theseparameters of physic-chemical and electrical properties of hydrogenated transformer oil relate to each other and have closed correlation with chemical composition.An aging bench was set up. Based on simulating the pratical working environmentincluding oxygen, temperature, electric field, metal and insulating materials, the oxidationstability of transformer oil could be researched more realistically and more accurately. Theresults show that the oxidation stability of hydrogenated transformer oil is much stronger thannaphthenic transformer oil in China and abroad.Modern transformer composed of many kinds of insulation materials is an integralinsulation system. To ensure the safe service, transformer oil should have excellentcompatibility with insulation materials. The influence of hydrogenated transformer oil onrubber seals, insulating paper and insulating varnish were researched. The results show thatthe hydrogenated transformer oil has good compatibility with rubber seals, insulating paperand insulating varnish.In order to further verify the reliability of hydrogenated transformer oil in powertransformers, the110kV transformer with hydrogenated transformer oil started to carry loadto operate. This transformer has been being regularly monitoring and it has been operating inthe good condition according to the testing data. The dielectric loss factor of hydrogenatedtransformer oil is even better than naphthenic transformer oil.